Nannie Doss did not match anyone’s image of a serial killer. A plain and rather scatterbrained grandmother, she might have never been caught had she not voluntarily agreed to an autopsy of her fifth husband, Samuel Doss, who died in 1954 after eating a bowl of prunes.

The prunes, it turned out, were poisoned.

Tulsa police quickly delved into Doss’ tangled life history, and found that 11 people with ties to her had died under mysterious circumstances. Doss insisted she only killed four of them — all men she had met and married through lonely hearts clubs after divorcing her first husband.

Doss said all four dead husbands had been given rat poison in their food or drink. Her third victim’s last words were said to have been, “I shouldn’t have had that last cup of coffee.”

Doss pleaded guilty to murdering Samuel Doss and died in prison. While she benefited from small life insurance policies on her dead husbands, Doss seems to have killed them mostly because they annoyed her. Samuel Doss, she complained, wouldn’t let her listen to the radio programs she wanted.